ive been trying to install my stupid autometer airfuel gaugue for the past 5 hours ..and still not working .... i spliced the ecu wire on pin number 4 witch is white .. and suppose to be the oxygen sensor wire .. but the damm gaugue just doesnt read anything .. ?? has anybody have the same set up ?? i know my o2 is good cause i connected my gaugue directly on it on its was working fine .. the reason i want it directly on the computer wire is i dont like loose wires in my engine bay .. it looks crummy ...

please tell me am i doing something wrong ?? !!!!!!!

Hi Alexandre,

Try this: http://www.dsmreviews.com/dsmreviews.php3?category=9003

or this: http://www.google.com/search?num=50...re+dash +autometer+air+fuel+&spell=1

If your DSM is a first gen, there is also the o2 wire located behind the glove box. (I'm not sure if it is also located here for 2G)

If you remove the glove box (very easy to do) it makes finding this wire a hell of a lot easier than shoving your arm up behind the box and trying to feel for the wire. (it's the only wire taped to a descending wire bundle with a female spade connector on it. It's 'way' up there...

http://www.google.com/search?sourceid=navclient&q=dsm+o2+wire+dash

Sorry I can't offer more help.

Good luck

I can tell you one thing... you do NOT want to connect the gauge directly to the O2 sensor wire!

why????

Hi Darko,

Huh?
Myself and about X number of members from dsm.org have built and used this: http://www.myzero.com/gauges/afgauge.html

I have never read of a problem by connecting to the o2 wire from behind the glove box.

Can you explain your thoughts?

...time ticks by, I re-read your post...

I think your talking about when Alexandre connected his Autometer directly to the o2 wires in the engine bay. Correct?

Cheers!

By doing this you actually change the voltage of the wire. Marta said it best at the SO. It is a heizenburg principle of actually changing the value of the thing you are tring to measure.

Don't believe me? Look at the EGT guage in your car. What happens at cold junctions? A drop in voltage. A goof Gauge will compensate.

can someone tell me or send me a pic of the wire that is located behind the glove box ?? your links dont work .. well the only one that seams to tell where the wire is ?? !!

thx alot

Try this one: http://www.myzero.com/electrical/find-o2.html

Maybe you guys misunderstood me...

I meant you don't want to connect the gauge DIRECTLY to the wire coming out of the o2 sensor. Like Waldo said, this changes the voltage in the wire and gives wrong readings to the ECU.

I think Norm and Marta can attest to how many problems this can cause.

Hi Waldo,

"Heisenberg principle" I wonder how much I have shifted my ECU away from it's quantum computations with the amount of modifications I have done to my wiring? )

I don't have an EGT, so I can't comment on that one directly.

Is the o2 cell a thermal resistor like an EGT probe? I would imagine that just touching the EGT probe would induce a signal change, however if the o2 is not a thermal resistor it's value should not change by the touch of some chilly Fluke97 probes.

Any who, I'm not sure how much load a LM3914N places on the signal from the o2 cell to the ECU. But I have calibrated my circuit to show the reference signal (o-1v) that the cell is 'suppose' to provide. In doing so, I have no idea what happen to the signal my quantum ECU now receives.

However, like I said before, I have never read here, online, dsm.org, the dsm list (when it use to run) that this circuit ever caused a problem with the ECU and the signal from the o2 cell.

(I do agree with you, any load placed on a signal will change the original. However if the impedance of the test/measurement equipment is high enough a measurement should be able to take place without throwing the original signal too far from spec, well ok, as long as were not talking about a quantum ECU

((- Before anyone gets the idea that I don't understand that Waldo and Darko are talking about connecting directly to the o2 cell vs. what I'm talking about is the wire behind the glove box. I do realize were talking about two separate locations. I'm just having a little fun while I should be working. Thanks -))

BTW, sorry about Sheila, but you tag line is quite funny.

Cheers,

I don't want to get too far off the topic of this thread so check out the one I started about EGT gauges & thermocouples.

Here's a bit of it...

Just FYI.
The EGT probe is a thermocouple.
A thermocouple is not a thermal resistor.
The thermocouple produces a very small voltage thru a process called the Seebeck effect. You do not have to supply any power to the probe for it to work.

Rob

Thanks Rob, my mistake, that's good to know.

Cheers!